Enabled Modules
Menu path: Settings > Settings > Enabled Modules
In case you don't use a certain module, you can disable this module here.
The items belonging to this module will not be removed. Simple uncheck the checkbox to disable a module and
check it to enable a module. Press "save" and the settings are applied.
Disabling the Loan functionality
In case you are not using the loan system you can disable this functionality by disabling the "contact person" module.